Tetramorium tyrion, Garcia & Fisher, 2012

Garcia, Francisco Hita & Fisher, Brian L., 2012, The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region — taxonomy of the T. bessonii, T. bonibony, T. dysalum, T. marginatum, T. tsingy, and T. weitzeckeri species groups, Zootaxa 3365, pp. 1-123 : 115-116

Tetramorium tyrion sp. n.

( Figs 156 , 161, 162, 163 )

Holotype worker, MADAGASCAR, Tulear , Bereboka, 60 km N.E. Morondava, collection code B.M. 1983-201, 18–23.V.1983 (J.S. Noyes & M.C. Day) ( BMNH: CASENT0249085 ).

Diagnosis

Tetramorium tyrion is not likely to be confused with the other species of the group due to its unique character combination of short erect pilosity on the first gastral tergite and very minute propodeal teeth.

Description

HL 0.65; HW 0.63; SL 0.46; EL 0.14; PH 0.31; PW 0.42; WL 0.77; PSL 0.07; PTL 0.19; PTH 0.24; PTW 0.16;

PPL 0.21; PPH 0.25; PPW 0.25; CI 96; SI 74; OI 22; DMI 55; LMI 40; PSLI 10; PeNI 38; LPeI 77; DPeI 86; PpNI 60; LPpI 84; DPpI 119; PPI 156 (one measured).

Head weakly longer than wide (CI 96). Anterior clypeal margin with distinct median impression. Frontal carinae moderately developed and fine, ending shortly after level of posterior eye margin. Antennal scrobes absent. Antennal scapes short, not reaching posterior head margin (SI 74). Eyes comparatively small (OI 22). Mesosomal outline in profile flat, weakly marginate from lateral to dorsal mesosoma, promesonotal suture and metanotal groove absent; mesosoma comparatively stout (LMI 40). Propodeum armed with minute broadly triangular teeth (PSLI 10). Propodeal lobes well-developed and broadly triangular, much more voluminous than propodeal teeth. Petiolar node in profile rectangular nodiform, approximately 1.3 times higher than long (LPeI 77), anterior and posterior faces approximately parallel, anterodorsal and posterodorsal angles at about same height, dorsum not tapering backwards posteriorly; node in dorsal view 1.3 times longer than wide (DPeI 86). Postpetiole in profile rounded, approximately 1.2 times higher than long (LPpI 84), in dorsal view 1.2 times wider than long (DPpI 119). Postpetiole in profile a bit more voluminous than petiolar node, in dorsal view approximately 1.5 times wider than petiolar node (PPI 156). Mandibles unsculptured, smooth and shiny; clypeus with strong median longitudinal ruga and one very weak rugula at each side; cephalic dorsum between frontal carinae with one moderately developed longitudinal median ruga, area between median ruga and frontal carinae almost unsculptured, traces of rugulae present anteriorly, median ruga of same length as frontal carinae; lateral head mostly unsculptured with weak irregular longitudinal rugulae anteriorly. Ground sculpture faint. Mesosoma laterally with irregular rugae or rugulae, dorsally mainly unsculptured with traces of rugulae only, petiole laterally weakly sculptured, dorsally unsculptured, postpetiole and gaster unsculptured, smooth and shining. All dorsal surfaces of body with short, fine erect pilosity. Whole body of uniform brownish colour.

Notes

Tetramorium tyrion is only known from the holotype from the type locality Beroboka, which is situated close to the Tsingy de Bemaraha National Park in Central Western Madagascar. Unfortunately, very little is known about the biology of T. tyrion or the habitat characteristics of its type locality. Hopefully, future sampling projects in the area will find some more specimens of this very rare species.

The T. tsingy group is a very small group based on just three specimens. This very limited material makes it relatively difficult to evaluate actual levels of intraspecific variation. The two specimens of T. tsingy differ in several aspects from the holotype of T. tyrion . The most obvious difference is the pilosity/pubescence on the first gastral tergite, which consists of short erect pilosity in T. tyrion , whereas T. tsingy has only short, strongly appressed pubescence. Also, both differ in their development of propodeal armament since T. tsingy has moderately short, triangular spines while T. tyrion possesses only very short and minute teeth. In addition, T. tsingy displays a better developed and more voluminous peduncle in comparison to T. tyrion . We believe the aforementioned character differences are significant enough to warrant describing T. tyrion and T. tsingy as distinct species. However, more material is necessary to support the species boundaries presented herein, or to provide arguments for any taxonomic change.

Etymology

The name of this unique and very characteristic new species is dedicated to the fictional character "Tyrion Lannister" from George R. R. Martin's epic fantasy series "A Song of Ice and Fire". The species epithet is a noun in apposition, and thus invariant.

Material examined

MADAGASCAR: Tulear, Bereboka, 60 km N.E. Morondava, 18–23.V.1983 (J.S. Noyes & Day, M.C.).

Figures

FIGURES 156 & 157. 156. Body of T.tyrion in profile showing the minute propodeal teeth and short, fine erect pilosity on the first gastral tergite—CASENT0249085 (Estella Ortega 2011). 157. Body of T. tsingy in profile showing the moderately short propodeal spines and short and strongly appressed pubescence on the first gastral tergite—CASENT0426807 (Shannon Hartman 2011).

FIGURES 161–163. T. tyrion, holotype—CASENT0249085 (Estella Ortega 2011). 161. Body in profile. 162. Body in dorsal view. 163. Head in full-face view.